This invention relates to semiconductor integrated circuit structures. More particularly, it is concerned with monolithic integrated circuit structures for the fabrication of semiconductor integrated circuit devices therein and to methods of producing such structures.
In the manufacture of monolithic semiconductor integrated circuits it is necessary that the structure in which the integrated circuit devices are fabricated provide for electrical isolation between the devices as may be required to prevent undesired interactions between them. Typically semiconductor integrated circuit structures contain a plurality of regions which are electrically insulated from each other or may be electrically isolated from each other by the application of appropriate biasing potentials. For certain types of device structures it is desirable to include so-called buried layers of relatively high conductivity in underlying portions of the regions in order to provide enhanced device and circuit performance. Conventional processes of fabricating monolithic semiconductor integrated circuit structures having electrically isolated regions with buried layers are complex and expensive.